5,709 research outputs found

    In vitro regeneration of Basella alba L

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    Basella alba L. is a tropical vine used as a vegetable in some Asian and African countries. It has potential as a nontraditional crop for small family farms. A short day plant, it blooms during the fall, provided the temperatures are mild. In the southeastern U.S., the short days of fall are associated with subfreezing temperatures, and plants are killed before blooming. Attempts were made to regenerate the plant using tissue culture techniques. Several trials were conducted with different media, hormones, and explants. It was found that nodal segments on Gamborg medium regenerated shoots. Interaction studies of auxins and cytokinins indicated that its endogeneous auxin content might be high because callus proliferated in almost all treatments and roots initiated even when the medium was not supplemented with an auxin

    Single-molecule study for a graphene-based nano-position sensor

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    In this study we lay the groundwork for a graphene-based fundamental ruler at the nanoscale. It relies on the efficient energy-transfer mechanism between single quantum emitters and low-doped graphene monolayers. Our experiments, conducted with dibenzoterrylene (DBT) molecules, allow going beyond ensemble analysis due to the emitter photo-stability and brightness. A quantitative characterization of the fluorescence decay-rate modification is presented and compared to a simple model, showing agreement with the d4d^{-4} dependence, a genuine manifestation of a dipole interacting with a 2D material. With DBT molecules, we can estimate a potential uncertainty in position measurements as low as 5nm in the range below 30nm

    Global variation of COVID-19 mortality rates in the initial phase

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    Objectives: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused devastation in over 200 countries. Italy, Spain, and the United States (US) were most severely affected by the first wave of the pandemic. The reasons why some countries were more strongly affected than others remain unknown. We identified the most-affected and less-affected countries and states and explored environmental, host, and infrastructure risk factors that may explain differences in the SARS-CoV-2 mortality burden. Methods: We identified the top 10 countries/US states with the highest deaths per population until May 2020. For each of these 10 case countries/states, we identified 6 control countries/ states with a similar population size and at least 3 times fewer deaths per population. We extracted data for 30 risk factors from publicly available, trusted sources. We compared case and control countries/states using the non-parametric Wilcoxon rank-sum test, and conducted a secondary cluster analysis to explore the relationship between the number of cases per population and the number of deaths per population using a scalable EM (expectation–maximization) clustering algorithm. Results: Statistically significant differences were found in 16 of 30 investigated risk factors, the most important of which were temperature, neonatal and under-5 mortality rates, the percentage of under-5 deaths due to acute respiratory infections (ARIs) and diarrhea, and tuberculosis incidence (p < 0.05) Conclusion: Countries with a higher burden of baseline pediatric mortality rates, higher pediatric mortality from preventable diseases like diarrhea and ARI, and higher tuberculosis incidence had lower rates of coronavirus disease 2019-associated mortality, supporting the hygiene hypothesis

    Role of social media and the Internet in pathways to care for adolescents and young adults with psychotic disorders and non-psychotic mood disorders

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    AIMS: Although psychosis often occurs during adolescence, there has been little research on how the ubiquitously used Internet and social media could impact pathways to care. We examined how youth with psychotic spectrum disorders (PSD) versus non-psychotic mood disorders (NPMD) use online resources in the early illness stages. METHODS: Social media use and pathways to care data were collected using a semi-structured interview from 80 youth (PSD = 40 and NPMD = 40) aged 12-21 years within 2 years of symptom onset. RESULTS: A total of 97.5% of participants (mean age = 18.3 years) regularly used social media, spending approximately 2.6 +/- 2.5 h per day online. There were 22.4% of our sample (PSD = 19.4%, NPMD = 25.0%, P = 0.56) who reported waiting to reach out for help believing that symptoms would disappear. A total of 76.5% (PSD = 67.5%, NPMD = 85.0%, P = 0.06) noticed social media habit changes during symptom emergence. Thirty per cent reported discussing their symptoms on social media (PSD = 22.5%, NPMD = 37.5%, P = 0.14). NPMD patients sought information most on how to stop symptoms (40.0% vs. 13.5%, P = 0.01), while PSD youth were more commonly interested in what caused their symptoms (21.6% vs. 15.0%, P = 0.45). More PSD patients (42.9% vs. 25.0%, P = 0.10) would prefer to receive mental health information via the Internet. Altogether, 63.6% (PSD = 64.9%, NPMD = 62.5%, P = 0.83) were amenable to clinicians proactively approaching them via social media during symptom emergence. A total of 74.3% (PSD = 78.4%, NPMD = 70.0%, P = 0.40) liked the idea of obtaining help/advice from professionals via social media. CONCLUSIONS: The Internet and social media provide an unparalleled opportunity to supplement and potentially transform early intervention services, and acceptance of this approach appears to be high

    Clinical features and management of malignant ascites

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    Retrospective analysis of 45 patients (33 females, 12 males) with cytologically-proven malignant ascites is presented. Abdominal pain was the most frequent symptom (69%). Fiftythree percent cases had low serum albumin. Ascitic fluid was haemorrhagic or serosanguinous in 48% cases, in the rest it was clear or straw-coloured. Peritoneal effusion was exudative in 84% cases. Mean glucose content of ascitic fluid was 95 mg/dl and the mean white cell count of 919 cells/cmm. Vast majority (82%) of the cases had metastatic adenocarcinomas. Primary malignancy was mostly ovarian (47%) followed by non-Hodgkin\u27s lymphoma (11%) and gall bladder carcinoma (9%). Primary site could not be identified in 13% cases. Sixty-two percent patients received systemic chemotherapy for the underlying malignancy, of these 43% had complete or partial resolution of the ascites. Of the patients whose long-term follow-up is available, 54% were alive with a median follow-up of 9 months

    Monitoring of traffic using unmanned aerial vehicle in Malaysia landscape perspective

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    The theoretical investigation has been performed on the implementation of optical Mobius shape in add-drop microring resonator. The modified add-drop Mobius configuration is used to investigate the optical bistability and the spectral transmission. The optical bright soliton pulse is used as the input source of the resonator system. The pulses propagation of the resonator system is modelled using the iterative programming based on the transfer matrix analysis equations. The enhancement of nonlinear effect of the resonator system is achieved by the add-drop Mobius resonator configuration. The system has been modelled for a variation of coupling coefficient for increase the bistable signal properties. The Add-drop Mobius MRR generated a bistable signal with 6.01 mW hysteresis width, and 9.47 mW output switch power with optimized radius of 5 µm outer and 4.5 m inner ring parts with 50 mW controlled power and input power. Mobius configuration is found as the better shape of resonator cavity that capable of optical switching application

    Modelling Merging Behaviour of Drivers in Heterogeneous Traffic at Roundabouts

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    Roundabouts are among the widely used traffic control infrastructures, which function by defining priorities for various entry approaches and circulating traffic. In many developing countries, the priority rules are not implemented through pavement markings or road signs and drivers are also unaware of these rules. Thus, available gaps become the only criteria for merging and movement of vehicles through the roundabout. It has been observed that the gap acceptance behaviour of drivers also depends on the type of vehicle in heterogeneous traffic streams. The main objective of this study is to investigate the difference in gap acceptance behaviour of motorcycle riders and car drivers at roundabouts. The gaps accepted by car drivers and motorcycle riders under different traffic conditions are measured from the recorded video of the traffic stream at a selected roundabout using an unmanned aerial vehicle. The critical gap is estimated using Raff’s method and its relationship with circulatory volume and approach speed is analysed. The results show that the critical gap for motorcycles (2.46 seconds) is 23.3% smaller than the critical gap for cars (3.21 seconds). Motorcycles can move through smaller gaps in comparison with cars due to their size and ease of manoeuvring. Results also show that motorcycles tend to merge with greater approach speed as the available gap within the circulating vehicles reduces, whereas the cars are observed following an opposite trend

    Risk factors for multidrug-resistant tuberculosis in urban Pakistan: A multicenter case-control study

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    Objective: To evaluate risk factors for multidrug-resistant tuberculosis (MDR-TB) in an urban setting of Pakistan.DESIGN AND Methods: In this multicenter case-control study, patients aged 15years old or older with sputum culture and sensitivity (C/S) diagnosed with pulmonary MDR-TB were defined as cases, whereas patients aged 15years old or older with sputum C/S diagnosed and susceptible to pulmonary TB were regarded as controls. Fifty cases and 75 controls were enrolled from three tertiary-care hospitals in Karachi.Results: Multivariable logistic regression models showed that cases were more likely to have had a TB patient in the house prior to the diagnosis of MDR-TB (adjusted odds ratio [ORadj]=3.1, 95% confidence interval [CI]: 1.2, 8.3) or had a history of prior TB treatment (ORadj=4.2, 95% CI: 1.1, 15.4). Furthermore, cases compared with controls tended to be male (ORadj=3.6, 95% CI: 1.4, 9.7), 15-25years of age (ORadj=3.7, 95% CI: 1.2, 11.3), of Sindhi ethnicity (adjusted OR=9.1, 95% CI: 1.9, 43.4) or with low educational attainment (ORadj OR=5.5, 95% CI: 1.7-17.6, for no formal schooling; ORadj=3.8, 95% CI: 1.1-14.1, 1 for 1-5 school years).CONCLUSIONS: A TB patient in the house or a history of prior TB treatment was strongly associated with MDR-TB in this study. Furthermore, younger age, male gender, Sindhi ethnicity and poor educational attainment entailed a high risk for MDR-TB. Targeted educational intervention for patients and their contacts may minimize the noncompliance with prescribed TB treatment and lessen MDR-TB magnitude in settings like Karachi
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